Thermosetting compositions containing isocyanurate ring

ABSTRACT

The invention relates to thermosetting compositions containing isocyanurate ring(s) prepared through chain extension of an epoxy resin (a) with carboxyl-functional oligomers (b), which are the reaction product of polyols (i) containing one or more isocyanurate ring(s) and polycarboxylic acids or their anhydrides (ii). The polyols (i) containing one or more isocyanurate ring(s) can be prepared from the reactions of tris (2-hydroxyalkyl) isocyanurates with a modifier from a caprolactone or alkylene oxide, or glycidyl ester or glycidyl ether and mixtures thereof. The epoxy-functional thermosetting compositions containing an isocyanurate ring(s) can be further reacted with unsaturated acids, preferably (meth)acrylic acid, to obtain a curable polyacrylate. Both epoxy-functional isocyanurate and acrylate-functional isocyanurate thermosetting compositions can be further modified with a polyisocyanate to produce a composition that is useful as a reactive adhesive, binder or in other applications.

FIELD OF THE INVENTION

This invention relates to a thermosetting composition containingisocyanurate rings. The isocyanurate ring is incorporated into thethermosetting composition through chain extension of the thermosettingresin.

BACKGROUND OF THE INVENTION

Tris (2-hydroxyalkyl) isocyanurates are commercial raw materials thathave been used for preparing coating resins and thermosettingcompositions containing an isocyanurate ring. The presence of anisocyanurate ring can improve the properties of the resins such asresistance towards thermal aging, weathering, UV light, low shrinkage,or improved mar resistance. Tris (2-hydroxyalkyl) isocyanurates can beincorporated into coating resins and thermosetting compositions as apolyol in the synthesis of polyester or polyether. However, there aredisadvantages of using tris (2-hydroxyalkyl) isocyanurates, such as itshigher melting point, higher viscosity, low solubility, low reactivity,and less flexible, as a polyol in the synthesis of a polyester orpolyether. To overcome such disadvantages, some modified tris(2-hydroxyalkyl) isocyanurates and their derivatives have been reported.For example, U.S. Pat. No. 5,268,428 discloses the use of caprolactoneand tris (2-hydroxyethyl) isocyanurates (THEIC) to prepare hydroxylfunctional polyester used in binder compositions. U.S. Pat. No.5,747,590 reported the use of caprolactone/THEIC oligomers for coatingcompositions. U.S. Pat. No. 7,425,594 reported copolymers produced fromthe reaction of glycidyl ester and/or ether with THEIC.

Tris (2-hydroxyalkyl) isocyanurates and their derivatives have also beenused as cross-linking agents for epoxy and polyurethane resins. U.S.Pat. No. 4,942,215 describes a reaction product of THEIC and anequivalent quantity of one or more anhydrides, which is combined withepoxy resin and liquid anhydride in a thermosetting liquid moldingcomposition. U.S. Pat. No. 6,667,078 describes a reaction product ofacid anhydride and THEIC as a curing agent in the manufacture of atransparent resin plate for a liquid crystal display. The use of thereaction product of polycaprolactone and THEIC in a urethane coatingcomposition has been described in U.S. Pat. No. 3,784,503.

JP Patent No. 60123478 describes an ester compound containing anisocyanuric ring having improved heat resistance and surface hardnessfree from brittleness, which is liquid at normal temperature and easilyhandleable, produced from a reaction product of epsilon (6)-caprolactonemodified tris(hydroxyalkyl) isocyanurate and acrylic acid or methacrylicacid.

Tris (2-hydroxyalkyl) isocyanurates and their derivatives have also beenused to produce epoxy resins. U.S. Pat. No. 3,763,097 describes apolyether epoxy resin prepared by reacting diepoxides with THEIC underthe acid pH conditions. U.S. Pat. No. 5,003,040 describes modified epoxyresins prepared from the reaction of diglycidyl ether and THEIC in thepresence of an etherification catalyst. The modified epoxy resin has anaverage of 1.5 to 2.5 epoxy groups and at least one primary hydroxylgroup per molecule. A curable coating composition based on a modifiedepoxy resin is described in U.S. Pat. No. 5,066,763. JP Patent No.2007099901 describes an epoxy resin with low curing shrinkage,transparency, excellent light fastness, and low yellowing under hightemperatures. The epoxy resin is obtained by reacting a polycarboxylicacid compound (A) and a non-aromatic epoxy resin (B) under a basiccatalyst, wherein the compound (A) is obtained by reacting tris (hydroxyalkyl) isocyanuric acid and an anhydride of a saturated acid.

Many curable resins compositions made directly with tris(2-hydroxyethyl) isocyanurate exhibit application properties that areless than desirable. For example, some compositions can result in filmsthat do not exhibit sufficiently high strength or hardness. Othercompositions can result in films that are not sufficiently flexible.Still other compositions can result in films that are brittle. Otherproblems, such as wrinkling or poor adhesion (which can result indelamination) can also be experienced.

It is thus an object of this invention to develop a thermosettingcomposition that utilizes an isocyanurate-based polyol, and is capableof producing a cured resin having the desired properties describedabove.

DESCRIPTION OF THE INVENTION

The present invention provides thermosetting compositions containingisocyanurate rings, comprising the reaction product of:

(a) a polyepoxide containing at least two epoxide groups per molecule,and

(b) a carboxyl functional oligomer formed by reacting:

-   -   (i) a polyol containing one or more isocyanurate rings produced        from the reaction of tris-(2-hydroxyalkyl) isocyanurate or        derivative thereof with a modifier selected from a caprolactone,        an alkylene oxide, a glycidyl ester, a glycidyl ether, and        mixtures thereof,    -   with an equivalent quantity of    -   (ii) one or more polycarboxylic acids or anhydrides thereof;

wherein, the molar ratio of epoxy functional groups of component (a) tothe acid functional groups of component (b) is greater than 1.0, andpreferably greater than 1.5.

As used herein, the term “thermosetting compositions” meansthermosetting resin compositions and both terms may be used in thepresent invention with the same meaning (presence of a thermosettingresin).

Polyols (i) containing one or more isocyanurate rings used in theinvention are made from the reaction of a tris-(2-hydroxyalkyl)isocyanurate or derivative thereof with a modifier selected fromcaprolactones, alkylene oxides, glycidyl esters, glycidyl ethers, andmixtures thereof. The molar ratio of the hydroxyl groups of thetris-(2-hydroxyalkyl) isocyanurate to the functional groups, which maybe epoxy or cyclo-ester, in the said modifier may be from 0.25 to 4 andpreferably from 0.5 to 2. The said tris (2-hydroxyalkyl) isocyanurate ispreferably tris (2-hydroxyethyl) isocyanurate or tris (2-hydroxypropyl)isocyanurate.

From the reaction of component (a) with component (b) under theconditions as disclosed above, epoxy-functional thermosettingcompositions containing isocyanurate rings result.

Epoxy functional thermosetting compositions additionally bearingunsaturated epoxy ester groups can also be produced according to theinvention as the reaction product of components (a), (b) and of anadditional component (c), with components (a) and (b) being as definedabove and the said additional component (c) being an unsaturatedcarboxylic acid, particularly ethylenically unsaturated and preferablyselected from acrylic and/or methacrylic acid, in such a proportion withrespect to components (a) and (b) that both functional groups epoxy andunsaturated epoxy esters (bearing secondary OH group) are present in thefinal product. Such a composition, in particular with partial conversionof epoxy groups to unsaturated ester groups, is preferably used in dualcure compositions with successive or simultaneous polycondensation andfree radical cures.

According to another embodiment, the said component c) is selected insuch a proportion that all epoxy functional groups are converted tounsaturated epoxy ester groups, and when the said acid component c) isacrylic or methacrylic acid, the derived reaction product is thus apolyacrylate (multifunctional acrylate or methacrylate).

According to another embodiment, the said epoxy-functional thermosettingcompositions containing isocyanurate rings, resulting from the reactionof component (a) with component (b), can be further reacted via theepoxy groups with said unsaturated carboxylic acid(s) component (c), toconvert partially or totally (completely), the said epoxy groups to thecorresponding unsaturated epoxy esters, bearing a secondary hydroxyl andpreferably when the said unsaturated acid component (c) is (meth)acrylicacid to obtain a curable polyacrylate (multifunctional acrylate ormethacrylate) composition. The epoxy functional group in thethermosetting composition can be partially or completely reacted withthe said unsaturated acid, which enables to have different reactivity byfree radical route. When all epoxy free groups are converted to the saidunsaturated epoxy ester groups, either by direct route via the reactionbetween components (a), (b) and (c) or via the indirect route by furtherpost-reacting the epoxy-functional composition (product of (a)+(b)) withsaid component (c), the said composition is free radical curable and canpreferably be a curable polyacrylate composition when the said component(c) is acrylic and/or methacrylic acid.

Both epoxy-functional thermosetting compositions containingisocyanurates (isocyanurate rings) and unsaturated epoxyester-functional groups, preferably acrylate-functional groups, can befurther modified with a polyisocyanate, and are useful as a reactiveadhesive, binder and/or in other applications for thermosetting resins.

The thermosetting compositions of the present invention can be dissolvedin a solvent such as acetone, or a monomer such as styrene, to form aresin solution.

The thermosetting compositions containing isocyanurate rings of thepresent invention are prepared through multiple steps, and the detailsof each step are described below as follows:

(1) Preparation of Polyols (i) Containing One or More IsocyanurateRings:

Polyols containing one or more isocyanurate rings are prepared byreaction of tris-(2-hydroxyalkyl) isocyanurate or derivative thereof,with a modifier selected from caprolactones, alkylene oxides, glycidylesters, glycidyl ethers, and mixtures thereof. Unmodifiedtris-(2-hydroxyalkyl) isocyanurates are not suitable in the presentinvention as part of the polyol component due to the higher meltingpoint, higher viscosity, low solubility, low reactivity, and lessflexibility. Tris (2-hydroxyethyl) isocyanurates and tris(2-hydroxypropyl) isocyanurates are preferred for preparing theisocyanurate ring-containing polyols (i). The molar ratio of thehydroxyl groups from the tris-(2-hydroxyalkyl) isocyanurate component tothe functional groups from the said modifier component may vary from0.25 to 4, preferably from 0.5 to 2 in the reaction composition.

The reaction to form the said polyols (i) is typically conducted with acatalyst and at an elevated temperature, for example, as described in JPPatent No. 59157074. Tris (2-hydroxyethyl) isocyanurate can be reactedwith epsilon-caprolactone in a weight ratio of about (95:5) to (5:95),preferably about (80:20)-(20:80) to produce a modifiedtris(2-hydroxyethyl) isocyanurate (polyol (i)) having a flowing orflowable state with a viscosity of less than about 50,000 mPa·s (cP) at30° C. The reaction of cyanuric acid with alkylene oxides is described,for example, in J. Org. Chem. 28, (1963) 85-89, with the resultingproduct being a tris (2-hydroxyalkyl) isocyanurate containing primaryhydroxyl groups.

(2) Preparation of Carboxyl Functional Oligomers (Component (b)):

The carboxyl functional oligomers (b), are prepared by reaction of apolyol (i) containing one or more isocyanurate rings as described aboveat (1), with an equivalent quantity of one or more polycarboxylic acidsor their anhydrides. Acid anhydrides are preferred in the preparation ofthe carboxyl functional oligomers (b). Preferred acid anhydrides includemaleic anhydride, succinic anhydride, dodecenylsuccinic anhydride,itaconic anhydride, citraconic anhydride, adipic anhydride,hexahydrophthalic anhydride, methyl-hexahydrophthalic anhydride, nadicanhydride, endo-cis-bicyclo(2,2,1)-5-heptene-2,3-dicarboxylic anhydride,methyl nadic anhydride, tetrahydrophthalic anhydride,methyltetrahydrophthalic anhydride, phthalic anhydride andtetrachlorophthalic anhydride.

The reaction between isocyanurate-based polyols (i) and the aforesaidacids or anhydrides (ii) is typically conducted by heating the reagentsto a temperature of about 120 to 180° C., which can be conducted in thepresence of catalytic quantities of a basic organic compound containingnitrogen.

(3) Preparation of Thermosetting Compositions Containing IsocyanurateRings:

Thermosetting compositions containing isocyanurate rings are prepared bythe reaction of carboxyl functional oligomers as described above at (b)with an aliphatic, cycloaliphatic or aromatic polyepoxide (a), which isliquid at ambient temperature (20 to 25° C.) and contains two or moreepoxide groups per molecule. The molar ratio of epoxy functional groupsof (a) to the acid functional groups of (b) is greater than 1.0,preferably greater than 1.5, such that the reaction product containsepoxy functional groups. The reaction of polyepoxides (a) and carboxylfunctional oligomers (b) should be carefully controlled such that thethermosetting resin does not cross-link during the reaction.

In particular, the said polyepoxides (a) can be chosen from phenolglycidyl derivatives, for example, the bis-glycidyl derivatives ofbishydroxyphenylmethane and bishydroxyphenyl propane; polyglycidylethers of the condensation products of phenol with formaldehyde (epoxynovolac resins); N-glycidyl derivatives of aromatic amines such astetra-glycidylamino diphenylmethane and diglycidylaniline; glycidylesters such as diglycidyl phthalate, diglycidyl tetrahydrophthalate anddiglycidyl methyltetrahydrophthalate; di- or poly-glycidylethers of aglycol or triazine such as diglycidylether of cyclohexanediethanol anddiglycidylether of dihydroxycyclohexylmethane; triglycidylisocyanurates;and diolefin diepoxides such as cyclohexenedioxide and dicyclopentadienedioxide.

Of these, the polyepoxides derived from the reaction of bisphenol A withepichlorohydrin are preferred.

The epoxy-functional thermosetting compositions (resins) containingisocyanurate rings as disclosed in (3) above as resulting from thereaction of (a) with (b), can be further reacted with unsaturatedcarboxylic acids, for example, acrylic acid and methacrylic acid, toobtain a curable polyacrylate. The epoxy functional group in thethermosetting composition (resin) can be partially or completely reactedwith the unsaturated acid to have different reactivity by free radical.

Both epoxy-functional thermosetting compositions containing isocyanuraterings, and unsaturated epoxy esters functional groups, preferablyacrylate-functional thermosetting compositions containing anisocyanurate ring(s), can be modified with polyisocyanates and areuseful as a reactive adhesive, binder or in other applications. Theamount of polyisocyanate modifier can be from about 0.1 to 30% by weightof the total composition. The amount of polyisocyanate used in amodification reaction should be calculated based on the functionality ofthe composition such that the thermosetting composition will notcross-link during the polyisocyanate modification reaction. Theconditions to avoid such a non desirable cross-linking or gelation, arewell-known to one skilled in the art. See, for example, Paul Flory,Principles of Polymer Chemistry, Cornell University Press, NY, pp.348-361 (1953). The glass transition temperature (Tg) of thepolyisocyanate-modified thermosetting compositions containingisocyanurate ring(s) of this invention is generally less than 50° C. andpreferably less than 45° C.

Useful polyisocyanate modifiers that can be utilized include monomericpolyisocyanates such as isophorone diisocyanate, trimethylhexamethylenediisocyanate, dicyclohexylmethane diisocyanate, and toluenediisocyanate; isocyanurates and biurets of monomeric isocyanates such asthe isocyanurate of isophorone diisocyanate, the isocyanurate ofhexamethylene diisocyanate, or the biuret of hexamethylene diisocyanate;and oligomers or prepolymers of isocyanates. Oligomers or prepolymers ofisocyanates can be formed by the reaction of an excess of polyisocyanateequivalents with a compound containing more than one isocyanate reactivegroup.

The reaction of polyisocyanate and of the thermosetting compositioncontaining an isocyanurate rings can be carried out under mildconditions. Although it is not required, it is preferable to carry outthe reaction with the use of a catalyst. The reaction temperature can bebetween 0 and 100° C., with the reaction typically carried out atbetween room temperature and 75° C. The catalyst, if used, may be chosenfrom a number of catalysts known in the art that are functional topromote an isocyanate-hydroxyl reaction. Examples of such catalystsinclude tin compounds such as dibutyltin oxide and dibutyltin dilaurate.The said polyisocyanate-modified epoxy-functional thermosettingcomposition and/or the polyisocyanate-modified polyacrylate compositionas defined above can particularly be used in reactive adhesives orreactive binders.

The said polyepoxide (a) can be selected from the group consisting of analiphatic, cycloaliphatic or aromatic polyepoxides which are liquid atambient temperature (20 to 25° C.) and contain two or more epoxidegroups per molecule. Preferably, the said polyepoxide (a) is derivedfrom a reaction of bisphenol A with epichlorohydrin.

The said carboxyl-functional oligomer (b) can particularly comprise thereaction product of a polyol (i) containing one or more isocyanuraterings with an equivalent quantity of one or more carboxylic acids oracid anhydrides (ii) and preferably with said acid anhydride selectedfrom the group consisting of maleic anhydride, succinic anhydride,dodecenylsuccinic anhydride, itaconic anhydride, citraconic anhydride,adipic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalicanhydride, nadic anhydride, methylnadic anhydride, tetrahydrophthalicanhydride, methyltetrahydrophthalic anhydride, phthalic anhydride andtetrachlorophthalic anhydride.

Under ambient temperature conditions, the thermosetting compositions ofthe present invention can be dissolved in a solvent(s) or monomer(s)that give the composition good workability, to obtain a resin solutionhaving a viscosity of between about 20 and 20,000 mPa·s (cP).

Examples of suitable monomers include, among others, aromatic compoundssuch as styrene, alpha-methylstyrene, dichlorostyrene, vinylnaphthalene, vinyl phenol and the like; unsaturated esters such asacrylic and methacrylic esters, vinyl laurate, and the like; unsaturatedacids such as acrylic and alpha-alkylacrylic acids such as methacrylicacid, butenoic acid, allylbenzoic acid, vinylbenzoic acid, and the like;and halides such as vinyl chloride and vinylidene chloride; and nitrilessuch as acrylonitrile and methacrylonitrile; diolefins such asbutadiene, isoprene and methylpentadiene; esters of polycarboxylic acidssuch as diallyl phthalate, divinyl succinate, diallyl maleate, divinyladipate, dichloroallyl tetrahydrophthalate, and the like; and mixturesthereof.

The thermosetting compositions include the solvents used in thesynthesis of the reactive components as disclosed above, and preferablyadditional solvent(s) that can be added as a processing aid, e.g.,during formulation of the resin composition, in order to enhance itsapplication characteristics. The inclusion of solvent(s) can aid theflow and leveling of the applied resin or adhesive. Moreover, if theresin is applied by means of spraying, a solvent can be added to improvethe atomization of the resin composition.

Examples of useful solvents are acetates such as butyl acetate, hexylacetate, and octyl acetate; glycol ethers and glycol ether acetates suchas propylene glycol ether and propylene glycol monomethyl ether acetate;and ketones such as acetone, methyl ethyl ketone, methyl propyl ketone,methyl isobutyl ketone and methyl hexyl ketone.

The thermosetting composition according to the invention may furthercomprise an additive selected from the group consisting of organicfillers, inorganic fillers, thixotropic agents, dyes and inhibitors orit may further comprise a cross-linking agent.

Pigments, if used, can be incorporated as pastes prepared by usinggrinding resins or pigment dispersants according to methods well knownin the art. The term “pigments” is meant to encompass organic andinorganic compounds that are colored materials, fillers, metallic andflake materials, and other like materials known in the art.

The compositions of the present invention are particularly suitable foruse as a reactive adhesive, binder, curable laminate resin, andtwo-component epoxy resin. The compositions can be used in adhesives,molding compositions or laminate composite compositions. Compositionswith unsaturated ester groups are convenient for cure by free radicalroute. All compositions comprising epoxy groups (alone or in part) maybe used in epoxy thermosetting compositions.

Finally the invention also relates to a molded article, which resultsfrom the cure of at least one thermosetting composition as defined aboveaccording to the invention.

The following experimental examples illustrate but do not limit thescope of the present invention.

Example 1 Preparation of a Polyol (i) Containing Isocyanurate Ring

A reactor is charged with 641 g of tris (2-hydroxyethyl) isocyanurate(THEIC), 1103 g of ε-caprolactone and 0.2 g of tetrabutyl titanate undera nitrogen atmosphere. The mixture is heated to 140° C. for 6 hoursunder effective stirring to obtain a reaction product of polyol.

Example 2 Preparation of a Carboxyl Functional Oligomer (b)

A reactor is charged with 1692 g of polyol from Example 1, 1100 g ofhexahydrophthalic anhydride (HHPA) under a nitrogen atmosphere. Themixture is heated to 140° C. for 6 hours under effective stirring toobtain a reaction product of polycarboxylic acid oligomer.

Example 3 Preparation of a Polyepoxide (a) Solution

A reactor is charged with 576 g of polycarboxylic acid oligomer fromExample 2, 556 g of bisphenol-A diglycidyl ether and 0.3 g ofbenzyltriethylammonium chloride under a nitrogen atmosphere. The mixtureis heated to 120° C. for 5 hours under effective stirring to obtain areaction product of polyepoxide. 600 g polyepoxide is mixed with 400 gof acetone to obtain a 60% resin solution.

Examples 4 to 7 Preparation of a Polyacrylate

A reactor is charged with 517 g of polyol from Example 1, and 336 g ofhexahydrophthalic anhydride under an atmosphere of nitrogen with 5%oxygen. The mixture is heated to 140° C. for 5 hours under effectivestirring to obtain a reaction product of carboxyl-functional oligomer.The reactor is cooled to 120° C. and 830 g of bisphenol-A diglycidylether, 190 g of methacrylic acid, 0.5 g of toluhydroquinone and 0.5 g ofbenzyltriethylammonium chloride were added into reactor. The mixture isheated to 115° C. for 10 hours to obtain a polyacrylate.

1080 g of polyacrylate from Example 4 is mixed with 720 g of acetone toobtain a 60% resin solution (Example 5).

790 g of polyacrylate from Example 4 is mixed with 340 g of styrene toobtain a 70% resin solution (Example 6).

400 g of polyacrylate from Example 5 is heated with 10 g ofdiphenylmethane 4,4′-diisocyanate (MDI) and 0.02 g ofdibutyltindilaurate in 50° C. for 5 hours (Example 7).

Examples 8 to 10 Preparation of a Polyepoxide/Polyacrylate

A reactor is charged with 517 g of carboxyl functional oligomers fromExample 2, 556 g of bisphenol-A diglycidyl ether, 64 g of methacrylicacid, 0.2 g of toluhydroquinone and 0.3 g of benzyltriethylammoniumchloride under an atmosphere of nitrogen with 5% oxygen. The mixture isheated to 120° C. for 8 hours under effective stirring to obtain areaction product polyepoxide/polyacrylate.

600 g of polyepoxide/polyacrylate from Example 8 is mixed with 400 g ofacetone to obtain a 60% resin solution (Example 9).

440 g of polyepoxide/polyacrylate from Example 9 is heated with 9 g oftoluene diisocyanate (TDI) and 0.02 g of dibutyltindilaurate at 50° C.for 5 hours (Example 10).

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement which is calculated to achieve the same purpose maybe substituted for the specific embodiments shown. This application isintended to cover any adaptations or variations that operate accordingto the principles of the invention as described. Therefore, it isintended that this invention be limited only by the claims and theequivalents thereof. The disclosures of patents, references andpublications cited in the application are incorporated by referenceherein.

What is claimed is:
 1. An epoxy-functional thermosetting compositioncontaining isocyanurate ring(s), comprising the reaction product of: (a)a polyepoxide containing at least two epoxide groups per molecule; (b) acarboxyl functional oligomer comprising the reaction product of anequivalent quantity of: (i) a polyol containing isocyanurate ring(s)comprising the reaction product of a tris (2-hydroxyalkyl) isocyanurateor derivative thereof with a modifier selected from the group consistingof caprolactones, alkylene oxides, glycidyl esters, glycidyl ethers, andmixtures therefor, and (ii) one or more polycarboxylic acids or acidanhydrides thereof; and (c) an unsaturated carboxylic acid; wherein themolar ratio of epoxy functional groups in component (a) to acidfunctional groups in component (b) is greater than 1.0, and both epoxyand unsaturated groups are present.
 2. The composition according toclaim 1, wherein the molar ratio of epoxy functional groups to acidfunctional groups is greater than 1.5.
 3. The composition according toclaim 1, wherein all epoxy functional groups are converted tounsaturated epoxy ester-functional groups.
 4. The composition accordingto claim 1, wherein the epoxy groups are partially converted tounsaturated epoxy ester-functional groups.
 5. The composition accordingto claim 1, wherein the unsaturated carboxylic acid (c) is selected fromthe group consisting of acrylic acid and methacrylic acid.
 6. Thecomposition according to claim 5, wherein it is a curable polyacrylatecomposition.
 7. The composition according to claim 1, further comprisinga polyisocyanate.
 8. The composition according to claim 7, wherein saidpolyisocyanate is from about 0.1 to 30% by weight of the totalcomposition.
 9. The composition according to claim 1, further comprisinga cross-linking agent.
 10. The composition according to claim 1, whereinsaid polyepoxide (a) is selected from the group consisting of aliphatic,cycloaliphatic and aromatic polyepoxides which are liquid at ambienttemperature (20 to 25° C.) and contain two or more epoxide groups permolecule.
 11. The composition according to claim 10, wherein saidpolyepoxide is derived from a reaction of bisphenol A withepichlorohydrin.
 12. The composition according to claim 1, wherein saidacid anhydride is selected from the group consisting of maleicanhydride, succinic anhydride, dodecenylsuccinic anhydride, itaconicanhydride, citraconic anhydride, adipic anhydride, hexahydrophthalicanhydride, methylhexahydrophthalic anhydride, nadic anhydride,methylnadic anhydride, tetrahydrophthalic anhydride,methyltetrahydrophthalic anhydride, phthalic anhydride andtetrachlorophthalic anhydride.
 13. The composition according to claim 1,wherein said polyol (i) containing one or more isocyanurate rings is thereaction product of a tris (2-hydroxyalkyl) isocyanurate or derivativethereof with a caprolactone.
 14. The composition according to claim 1,having a glass transition temperature (Tg) below 50° C.
 15. Thecomposition according to claim 1, dissolved in a solvent, a monomer or amixture thereof.
 16. The composition according to claim 1, furthercomprising a processing aid selected from a solvent and a monomer. 17.The composition according to claim 1, further comprising an additiveselected from the group consisting of organic fillers, inorganicfillers, thixotropic agents, pigments and inhibitors.
 18. A moldedarticle, produced by curing a composition as defined according to claim1.